730 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



2. Unequally developed wings in the tico sexes.. — The wino\s of the 

 male often outrun those of the fennUe. The best-known instance i.s 

 the frequent anoulation of the anal area of the hind win«^ in the male, 

 the hind angle of the female always remaining rounded. In Jlaz/eninx 

 (Ho-. 23) it will be seen that the difference in conformation of the anal 

 angle has slightly affected the form of the anal loop also. 



In that part of the Calopterygine series in which the stigma is lost 

 it is retained longest in the females. . 



In Ai/rioii (tig. i, t.) it retains a much more primitive form in thet 

 female. The cuT'ious stigma of the fore wing of the male of Anom- 

 (thK/rioii (tig. 4, K.) has outstfipped that of the hind wing, l)ut event 

 the lattiM- is somewhat less primitive^ than either stigma in the female. , 



Fig. 23. — Wings of Ilagniins hrrviitti/lus Sei.ys. 



The reason for the greater specialization of the wings in the male is, . 

 of course, .so well known as to need only passing mention. The i 

 males, and not the females, seek their mates and compete for them i 

 upon th(^ wing, often amid great rivalry. 



SUMMARY OF TFIE MORE GENERAL TENDENCIES OF VEIN EVOLUTION WITHIN THE ORDER. . 



The facts of ontogeny and comparative anatomy hitherto presented '^ 

 seem to wari'ant a number of conclusions as to the development of the 

 several parts, which conclusions may be expressed in tabular form as '| 

 follows: 



Generalized condition . 



Subcosta long; nodus remote from 

 wing base. 



Antenodal and postnodal cross veins 

 numerous, weak, irregular (not matched), 

 and none of them hyj)ertrophied. 



Stigma without .special support. 



Developmental tendencie.t. 



Subcosta becoming shortened and the 

 nodus retracted. 



Antenodal and j)ostnodal cross veins 

 becoming reduced in number, stronger, 

 more regular, sometimes matched in 

 position or differentiated among them- 

 selves. 



Stigma ])ecoming supported, i)roxi- 

 mally by a brace vein (hypertrophied 

 cross vein), and distallv by a sector 



